Method system and device for assessing insulin sensitivity

ABSTRACT

A method and a system for determining insulin sensitivity (IS) is described. In one aspect the method and the system can be implemented by receiving a first parameter corresponding to an insulin dose in a subcutaneous tissue; applying a first kinetic model to obtain a plasma insulin concentration based on the first parameter; receiving a second parameter corresponding to a plasma glucose concentration; determining the insulin sensitivity (IS) based on the plasma insulin concentration and the second parameter.

RELATED APPLICATIONS

This application claims priority to U.S. patent application Ser. No.12/145,942 filed Jun. 25, 2008 which claims priority to U.S. ProvisionalApplication Ser. No. 60/937,247 filed Jun. 25, 2007, which is hereinincorporated by reference in its entirety.

FIELD OF THE INVENTION

Techniques and devices are described relating to sustained medicalinfusion of therapeutic fluids for patients. In particular, a method,system and device for assessing a diabetic state of the patient isdescribed. For example, the method, system and device can be used forassessing an insulin sensitivity value (“IS”). The assessed IS value canbe used, for example, to determine basal and bolus dosages of insulinprior to administrating it to the patient.

BACKGROUND OF THE INVENTION

Diabetes mellitus is a disease of a major global importance. The numberof individuals affected increases at almost epidemic rates, such that in2006, this number reached approximately 170 million people worldwide andis predicted to at least double over the next 10-15 years. Diabetes ischaracterized by a chronically raised blood glucose concentration(hyperglycemia), due to a relative or absolute lack of the pancreatichormone-insulin. Within healthy pancreas, beta cells that are located inthe islets of Langerhansand continuously produce and secrete insulinaccording to the blood glucose levels, thereby maintaining near constantlevels of glucose in the body. Long-term tissue complication affectsboth the small blood vessels (microangiopathy, causing eye, kidney andnerve damage) and the large blood vessels (causing acceleratedatherosclerosis, with increased rates of coronary heart disease,peripheral vascular disease and stroke). These complications heavilyburden the patients and health care resources that are necessary totreat the patients.

The Diabetes Control and Complications Trial (DCCT) demonstrated thatdevelopment and progression of chronic complications of diabetes areheavily related to the degree of altered glycemia, as quantified bydeterminations of glycohemoglobin (HbA1 c). [DCCT Trial, N Engl J Med1993; 329: 977-986, UKPDS Trial, Lancet 1998; 352: 837-853. BMJ 1998;317, (7160): 703-13 and the EDIC Trial, N Engl J Med 2005; 353, (25):2643-53]. Thus, maintaining normoglycemia, which may be accomplished byfrequently measuring glucose levels and accordingly adjusting an amountof delivered insulin, is of utmost importance.

Conventional insulin pumps can deliver insulin to the patient and can beconfigured to deliver rapid-acting insulin 24 hours a day through acatheter placed under the skin. The total daily dose (TTD) of insulincan be divided into basal and bolus doses. Basal insulin is deliveredcontinuously over 24 hours and keeps the blood glucose concentrationlevels (hereinafter, “blood glucose levels”) in normal desirable rangebetween meals as well as overnight. Diurnal basal rates can bepre-programmed or manually changed according to various daily activitiesof the patient. Insulin bolus doses are delivered before meals or duringepisodes of high blood glucose concentration levels to counteractcarbohydrates' loads.

The amount of insulin which should be present in the administered boluscan depend on several parameters, for example:

-   -   Amount of carbohydrates (“Carbs”) to be consumed, alternatively        defined as “serving”, wherein 1 serving equals 15 grams of        Carbs.    -   Carbohydrate-to-insulin ratio (“CIR”), i.e. an amount of        carbohydrate balanced by one unit of insulin which is measured        in grams per one unit of insulin.    -   Insulin sensitivity (“IS”), i.e. an amount of blood glucose        value lowered by one unit of insulin which is measured in mg/dL        (milligrams/deciliter) per one unit of insulin.    -   Current blood glucose levels (“BSC”) which is measured in mg/dL.    -   Target blood glucose levels (“TBG”), i.e. a desired blood        glucose level. TBG for most patients suffering from diabetes is        in the range of 90-130 mg/dL before a meal, and less than 180        mg/dL one to two hours after the start of a meal.    -   Residual insulin, i.e. an amount of stored active insulin        remaining in the body of the patient after a recent bolus        delivery. This parameter is relevant when there is a short time        interval between consecutive boluses (i.e. less than 5 hours).

Conventional insulin pumps can require users to constantly calculate orestimate appropriate pre-meal insulin bolus doses. These calculations orestimations can be based on the above mentioned parameters toeffectively control the blood glucose levels and maintain euglycemia.

Conventional portable insulin pumps can include bolus calculating meansthat operate based on inputs of meal carbohydrate content and glucoselevels by the patient. In these pumps, the calculated bolus dose can beautomatically delivered to the patient.

An example of such conventional pumps is discussed in U.S. Pat. No.6,936,029 assigned to Medtronic MiniMed. Such a pump provided with abolus calculator and an algorithm for calculating the amount of insulinto be administered is described. The algorithm is based on a formula forcalculating a bolus, depending on the user's IS, CIR, target BG and userinputs of blood glucose (BG) and carbs intake.

-   -   If the current BG is higher than the target BG, the recommended        bolus is calculated as:

${{Recommended}\mspace{14mu} {bolus}} = {\underset{\underset{\;^{''}{Food}\mspace{14mu} {estimate}^{''}}{}}{\left( {{TC}\text{/}{CIR}} \right)} + \left( {B\underset{\underset{\;^{''}{Correction}\mspace{14mu} {estimate}^{''}}{}}{{\left. {{SC} - {BST}} \right)\text{/}{IS}} -}{RI}} \right.}$

Wherein TC—total amount of carbohydrates; CIR—carbohydrate-to-insulinratio; BST—target blood sugar; BSC—current blood sugar; IS—Insulinsensitivity; RI—remaining insulin, i.e. “insulin on board”.

-   -   If the current BG is lower than the target BG, the recommended        bolus is calculated as:

Recommended bolus=(TC/CIR)+(BSC-BST)/IS

-   -   If the current BG is higher than the low target BG and lower        than the high target BG (e.g. current blood (BSC) glucose=105        mg/dL, target range (BST)=90-130 mg/dL) then the recommended        bolus is calculated as:

Recommended bolus=(TC/CIR)+0

Basal insulin can be delivered continuously over 24 hours, and can keepthe blood glucose levels in range between meals and overnight. Diurnalbasal rates can be pre-programmed or manually changed according tovarious daily activities. The basal insulin strongly depend on theuser's IS value.

Accurate assessment of the IS value can be critical for maintainingeuglycemia for diabetic patients. IS can also be essential indetermination of the administered basal dose and the administered bolusdose, especially the correction bolus.

Currently, many type 1 diabetes patients using rapid acting insulin(e.g. Humalog, Novolog) determine their IS value according to the “2200to 1600 rules”. The user's IS is established by dividing the valuecorresponding to an appropriate rule by the total daily dose ofrapid-acting insulin (e.g. if the total daily insulin dose is 40 unitsand the 1800 rule is used, the insulin sensitivity factor would be 1800divided by 40=45 mg/dl/unit). FIG. 1 shows the point drop per unit ofinsulin (insulin sensitivity) according to the various rules (adaptedfrom Using Insulin © 2003)

The derived IS value can be used when initially setting the basaldosages and the bolus calculator of many existing pumps or when the usercalculates the necessary bolus. Evaluation of the diabetic progression,especially in type 2 diabetes (insulin sensitivity is inversely relatedto insulin resistance, the primary etiology of type 2 DM), may bederived from the change in IS value (decreases as the diseaseprogresses).

Using the abovementioned “rules” can have several drawbacks:

-   -   The accurateness of the established IS value is low due to a        limited number of applied “rules”.    -   The values are not re-evaluated throughout the usage of the        bolus calculator. This poses a serious problem since the IS        value is not a static parameter. This shortcoming may be        especially significant for adolescent users due to relatively        frequent dynamics of this parameter during puberty.

SUMMARY OF THE INVENTION

A method and a system for determining insulin sensitivity (IS) isdescribed. In one aspect the method and the system can be implemented byreceiving a first parameter corresponding to an insulin dose in asubcutaneous tissue; applying a first kinetic model to obtain a plasmainsulin concentration based on the first parameter; receiving a secondparameter corresponding to a plasma glucose concentration; determiningthe insulin sensitivity (IS) based on the plasma insulin concentrationand the second parameter.

In one implementation, the second parameter can be determined byapplying a second kinetic model to a glucose concentration measured inthe subcutaneous tissue. For example, the glucose concentration in thesubcutaneous tissue can be measured using at least one of a glucometerand a Continuous Glucose Monitor (SCGM).

In one implementation, the insulin sensitivity (IS) can be determinedusing one or more of conventional plasma glucose-plasma insulin dynamicsmodels. For example, the dynamics models can comprise at least one ofthe Homeostatic Model Assessment (HOMA), and Quantitative InsulinSensitivity Check Index (QUICKI).

In one implementation, the insulin sensitivity (IS) can be periodicallyreevaluated. For example, the insulin sensitivity (IS) can bereevaluated after a predetermined period of time since a last foodbolus. In some implementations, the insulin dose in the subcutaneoustissue can be a basal insulin dose.

In some implementations, the method and the system can be implemented byproviding a recommendation to a user to validate the determined insulinsensitivity value (IS). For example, the recommendation can be providedas a message displayed on a graphical user interface. In someembodiments, the user can optionally accept or reject the determinedinsulin sensitivity value (IS). In some embodiments, the determinedinsulin sensitivity value is accepted automatically.

In some implementations, the method and the system can be implemented byselecting an insulin bolus based on the determined insulin sensitivityvalue (IS) and delivering the insulin bolus to a user. For example, theinsulin bolus can be delivered using a remotely controlled skinsecurable pump, such that the pump is connectable to and disconnectablefrom the user's body. In some implementations, the glucose concentrationin the subcutaneous tissue can be measured using a glucometer integratedinto a remote control unit.

In some implementations, a system that employs a method capable ofassessing the user's IS can comprise a miniature skin adhered patch thatcan continuously dispense insulin and monitor body glucose concentrationlevels.

In some implementations, a semi closed loop system can be provided. Thesemi close loop system can monitor glucose levels and dispense insulinaccording to sensed glucose levels and according to an IS assessmentmethod.

In some implementations, a device that comprises an insulin infusion anda continuous glucose monitor patch unit can also be provided. Forexample, the monitor patch unit can comprise a disposable part and areusable part. The reusable part can contain all relatively expensivecomponents and the disposable part can contain cheap components, thusproviding a low cost product for the user and a highly profitableproduct for the manufacturer and payer. The device can employ a methodcapable of assessing the user's IS value.

In some implementations, an insulin infusion and a continuous glucosemonitor patch unit can also be provided. For example, the monitor patchunit can be remotely controlled and can employ a method capable ofassessing the user's IS value.

In some implementations, the IS assessment can be established viaprocessing of integrated information obtained from frequent glucosemeasurements (e.g. subcutaneous continuous glucose monitoring) and dataof the delivered basal insulin.

In some implementations, the IS assessment can be obtained from SCII(Subcutaneous Continuous Insulin Infusion), SC glucose sensing and theintegration of conventional mathematical models:

-   -   Various mathematical models of the plasma glucose-plasma insulin        dynamics exist in the literature. Some of these models have a        high predictive capability and were assessed in numerous        studies. Insulin sensitivity (IS) can be evaluated by virtue of        these models. These models however require the plasma insulin        and plasma glucose concentrations—data that may be acquired only        by direct blood sampling. In addition, plasma insulin requires a        lab analysis (as opposed to blood glucose which can be        determined by a portable glucometer).    -   There are mathematical models in the literature that exhibit the        relationship between plasma glucose and glucose in the        interstitial fluid (ISF).    -   There are mathematical models in the literature that exhibit the        relationship between plasma insulin and insulin in the ISF.

In some implementations, the IS assessment can be obtained from SCII,direct plasma glucose sensing, using a glucometer, and integration ofmathematical models exhibiting plasma glucose-plasma insulin dynamicsand the relationship between plasma insulin and insulin in the ISF.

In some implementations, the IS can be assessed using one or more ofconventional plasma glucose-plasma insulin dynamics models e.g. the“minimal” model is a mathematical model of the plasma glucose-plasmainsulin dynamics, proposed by the team of Bergman and Cobelli, the AIDA(www.2aida.org), the model of Sorenson (DIABETES TECHNOLOGY ANDTHERAPEUTICS, 2005 Vol 7 (1) 94-108). Alternative models which maysimplify the insulin sensitivity assessment are for example theHomeostatic Model Assessment (HOMA), and a more recent method is theQUICKI (Quantitative Insulin Sensitivity Check Index). Both employfasting insulin and glucose levels to calculate insulin sensitivity andboth correlate reasonably with the results of the gold standard clampingstudies and/or known parameter.

In some implementations, a time delay of 10-20 minutes can be determinedbetween the glucose measured in the ISF and the blood glucose. That is,an ISF glucose measurement made at time “t=20′” is equal to the bloodglucose at tome “t”.

In some implementations, the IS value can be constantly reevaluated.

In some implementations, the IS value can be reevaluated only in timeframes when at least five hours have passed since the last food bolus(e.g. during the night). The IS algorithm in such embodiments onlyconsiders the basal insulin.

In some implementations, if a new IS value has been determined, the usercan be recommended to pay a visit to his/her practitioner to validatethe new IS value, change the settings of the pump accordingly, andpossibly perform further tests to evaluate the diabetic state (e.g.HA1C).

In some implementations, if a new IS value is determined, the user mayaccept the automatically assessed new IS value and change the settingsof the device to deliver the following bolus and basal dosagesaccordingly. In some examples, the automatically assessed new IS valuemay be set without a user interface.

In some implementations, the user can be notified prior to IS valuere-setting and can suspend the re-setting or select an alternative ISvalue.

In some implementations, the IS value assessment method can beimplemented in an insulin infusion device comprising insulin dispensingpatch unit and a remote control unit, wherein a glucose sensingapparatus (e.g. glucometer) is integrated in the remote control unit.

In some implementations, the patch unit can be composed of two parts, areusable part that contains all electronic and driving elements and adisposable part that contains insulin reservoir. The glucose sensingapparatus (e.g. glucometer) may alternatively be integrated in thereusable part of the patch unit of the device. Preferably, the IS valueassessment method is implemented in the remote control unit of theinsulin infusion device. Alternatively, the IS value assessment methodcould be implemented in the reusable part of the patch unit of thedevice. In some implementations that use a glucose sensing apparatus ofthe device as a glucometer, frequent BG measurements can be performedfor the time of the test.

In some implementations, the IS value assessment method can beimplemented in the remote control unit of the device. Alternatively, themethod can also be implemented in the reusable part of patch unit of thedevice. Alternatively, the method can be implemented in both thereusable part of the patch unit of the device and the remote controlunit of the device.

In some implementations, the IS value assessment method can beimplemented by a device configured as a miniature patch that can beadhered to the skin and can continuously dispense insulin and frequentlymeasure glucose levels.

The IS value assessment method can be implemented in a remote unit of aninsulin dispensing device that can frequently measure glucose levels.The IS value assessment method can also be implemented in a devicecomprising a miniature skin adhered patch that can continuously dispenseinsulin and continuously monitor body glucose concentration levels.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the point drop per unit of insulin (insulin sensitivity)according to the various rules (adapted from Using Insulin © 2003).

FIGS. 2A-B show an exemplary insulin infusion device comprising aninsulin dispensing unit and a remote control unit that contains an ISassessment feature.

FIGS. 3A-B show an exemplary insulin infusion device containingcontinuous subcutaneous glucose monitors for providing blood glucosereadings (BG) for the IS assessment feature.

FIG. 4 is a block diagram showing one example of model integration.

FIG. 5 shows the “Koboyashi” model.

FIG. 6 shows a model of ISF glucose that can predict plasma glucose.

FIGS. 7A-C show exemplary insulin infusion device containing bloodglucose monitor in three different locations providing blood glucose(BG) readings for the IS assessment feature.

FIG. 8 shows another embodiment of the IS assessment feature assessmentfeature located in a remote control unit and PC.

DETAILED DESCRIPTION

FIGS. 2A-B show an insulin infusion device comprising a patch unit(1010), that can be securable to the patient's skin (5), and a remotecontrol unit (1008), that can communicate with the patch unit (1010),allowing programming, user inputs and data acquisition.

In some implementations, manual inputs can be carried out by buttons(not shown) located on the patch unit (1010). The patch unit (1010) canbe composed of one housing (1001) (FIG. 2A) or two housings (1001, 1002)(FIF 2B) containing a reusable part (1) and a disposable part (2)respectively.

The patch unit (1010) can comprise a cannula (6) that can penetrates theskin (5) to allow delivery of insulin. The patch unit (1010) can bedirectly attached to the patient's skin (5) by adhesive means (notshown) or can be attached to a dedicated needle unit (not shown) that isadhered to the patient skin (5) and allows the patch unit (1010)disconnection from and reconnection to the body as disclosed in ourprevious patent application U.S. Ser. No. 60/876,679, filed on Dec. 22,2006. The remote control unit (1008) may contain an insulin sensitivity(IS) assessment feature (3000).

FIGS. 3A-B illustrate several implementations, in which blood glucoselevel readings needed for the IS assessment feature can be received froma continuous subcutaneous glucose sensing apparatus (1006). Thecontinuous subcutaneous glucose sensing apparatus (1006) and the ISassessment feature (3000) which can be located in the remote controlunit (1008) can establish communication therebetween. This communicationcan allow programming, data handling, and user inputs.

FIG. 3A shows one implementation in which the current blood glucoseconcentration can be sensed via an independent continuous subcutaneousglucose sensing apparatus (1006). FIG. 3B shows an embodiment in whichthe continuous subcutaneous glucose sensing apparatus (1006) is locatedwithin the patch unit (1010) of the insulin delivery device. The insulindispensing apparatus (1005) and glucose sensing apparatus (1006) canconstitute a single delivery device, and may use a single cannula (6)for both dispensing and sensing. Alternatively (not shown), thedispensing apparatus (1005) and sensing apparatus (1006) can haveseparate cannulate that penetrate the skin (5) and reside in thesubcutaneous tissue.

The delivery device of this embodiment may be composed of two parts—areusable part (1) and a disposable part (2), each part has acorresponding housing (1001, 1002).

In some implementations, the device can contain a closed loop or semiclosed loop system. Insulin can automatically be dispensed according tocontinuous glucose level monitoring (closed loop) or according tocontinuous monitoring and additional pre-meal bolus user inputs (semiclosed loop). The IS assessment feature (3000) may be used for bolusinputs calculation in the semi closed loop system and for basal dosagesadministration in the closed and semi-closed loops.

FIG. 4 is a schematic block diagram that shows one example of thesuggested model, which integrates various sub-modules for the assessmentof the IS value. Conventional modeling of the physiologicalinsulin-glucose regulation system can require parameters that must besampled from the blood tissue (i.e. plasma).

The device disclosed hereinafter, can be attached to the patient's skinand can have accessibility to the subcutaneous tissue layer through thecannula. Thus, sensing of glucose concentration levels in the ISF(“interstitial fluid”) can be possible. In addition, the ISF insulininfusion can be carried out and controlled by the patch unit.

The application of “transitional models” (100, 101) can allow theutilization of insulin-glucose conventional models (102) with measuredparameters of the subcutaneous tissue (i.e. ISF). It follows that themodels (100, 101) can allow transition from the subcutaneous tissue toblood tissue: model (100) simulates the glucose kinetics, and the model(101) simulates the insulin kinetics. This integrated model (1000) canenables IS assessment via parameters which may be acquired thanks to thepresence of the adhered patch unit.

FIG. 5 shows an example of a model (102) that describes thepharmacokinetics of insulin after the administration of continuousinfusion in diabetic patients. According to Kobayashy et al., theone-compartment kinetic model can be applied to obtain the plasmainsulin from the ISF insulin as schematically shown in FIG. 5. K_(a) isthe first order absorption rate constant and K_(e) is the first orderelimination rate constant. V_(d) is the distribution volume.

The time course of plasma insulin concentration after continuoussubcutaneous infusion at a constant rate (RI) for a given period can becalculated by the following equation:

$I_{0} = {{\frac{RI}{V_{d} \cdot K_{e}} \cdot \left( {1 - ^{K_{e} - t}} \right)} + \frac{{RI} \cdot \left( {^{{- K_{e}}t} - ^{{- K_{a}} \cdot t}} \right)}{V_{d} \cdot \left( {K_{e} - K_{a}} \right)}}$

-   -   wherein:    -   I₀ is the plasma insulin concentration at time t during a        certain infusion period,    -   RI is a constant rate of insulin infusion to the subcutaneous    -   K_(e), K_(a), V_(d) are pharmacokinetic parameters.

In some implementations, RI is a parameter controlled by the infusiondevice.

Based on clinical investigation (Kobayashi et al., Diabetes 1983, vol.32, 331-336), an example for the pharmacokinetic parameters K_(e),K_(a), V_(d) is given below:

K _(a) (min⁻¹)=0.033±0.008

K _(e) (min⁻¹)=0.017±0.002

V _(d) (L/kg)=3.75±2.28

FIG. 6 shows an example of a model (102), proposed by K. Rebrin et al,wherein subcutaneous glucose predicts plasma glucose. The model candescribe plasma (C₁) and interstitial fluid (ISF; C₂) glucose kineticsassuming glucose equilibrates by diffusion (D=k₂₁V₁=k₁₂V₂) and iscleared from ISF by tissue surrounding the sensor (clearance=k₀₂V₂),where V₁ and V₂ represent plasma volume and ISF distribution volume seenby the sensor, respectively. To estimate the gradient and delay the massbalance equation for the ISF pool was first obtained as:

$\frac{C_{2}}{t} = {{{- \left( {k_{02} + k_{12}} \right)}C_{2}} + {k_{12}\frac{V_{1}}{V_{2}}C_{1}}}$

Where C₁ and C₂ are plasma and ISF glucose concentrations.

Hence, the ISF-to-plasma glucose gradient and the ISF equilibration timeconstant (delay) are:

${C_{1} = {\frac{k_{12} + k_{02}}{k_{21}\frac{V_{1}}{V_{2}}}C_{2}}};{\tau = \frac{1}{k_{12} + k_{02}}}$

-   -   (K. Rebrin et al., Am J Physiol Endocinol Metab 277:561-571,        1999)

The derivation of plasma glucose may be carried out by such a model in aclosed or semi-closed loop system. In alternative embodiments, plasmaglucose levels can be detected by a glucometer.

As a simple example, the model (102) for assessing the IS, can beassessed by the quantitative insulin sensitivity check index (QUICKI)suggested by Katz et al. The QUICKI is derived using the inverse of thesum of the logarithms of the fasting insulin and fasting glucose:

$\frac{1}{{\log \left( I_{0} \right)} + {\log \left( G_{0} \right)}}$

Where I₀ is the fasting plasma insulin and G₀ is the fasting plasmaglucose (G₀ is also designated in FIG. 5 as C₁). This index correlateswell with glucose clamp studies (r=0.78), and is useful for measuringinsulin sensitivity (IS), which is the inverse of insulin resistance(IR). In some implementations, these two parameters (I₀ and G₀)necessary for the model (102) can be obtained from the models (100) and(101) under the condition of fasting.

FIGS. 7A-C show three different embodiments of the device, each containsa glucometer (90) to be used as blood glucose (BG) inputs for the ISassessment feature (3000).

FIG. 7A shows a glucometer (90) located in the remote control unit(1008) of the device. The glucometer (90) can comprise an opening (95)for receiving of a test strip (99). The user extracts blood from thebody, places the blood on the test strip (99) and inserts the strip intothe opening. The glucose readings (90) are displayed on screen (80) ofthe remote control unit.

FIG. 7B shows a glucometer (90) located in the reusable part (2) of thepatch unit (1010). A communication channel (300) between the glucometer(90) residing in the patch unit (1010) and the IS assessment feature(3000) residing in the remote control unit (1008) is maintained,allowing programming, data handling, and user inputs.

FIG. 7C shows an embodiment in which glucose readings are directly orremotely (90) received from an independent glucometer.

FIG. 8 shows another embodiment of the device, where the IS assessmentfeature (3000) is located in a remote control unit (1008) thatcommunicates with an external PC (50).

In some implementations, any change of the parameters representing thediabetic state of the user (e.g. IS value) can be saved and may bedisplayed in any graphical or non-graphical manner. The saved data canautomatically be sent to the user's practitioner (e.g. by electronicmail) for evaluation, validation or any other clinical intervention.

Any and all patents, applications, articles and/or publicationsreferenced in this specification are hereby incorporated by referenceherein in their entireties.

Although illustrative embodiments of the invention have been describedin detail herein with reference to the accompanying drawings, it is tobe understood that the invention is not limited to those embodiments,and that various changes and modifications can be effected therein byone skilled in the art without departing from the scope and spirit ofthe invention.

It is noted that in this disclosure and particularly in the claimsand/or paragraphs, terms such as “comprises,” “comprised,” “comprising,”and the like can have the meaning attributed to it in U.S. patent law;that is, they can mean “includes,” “included,” “including,” and thelike, and allow for elements not explicitly recited. These and otherembodiments are disclosed or are apparent from and encompassed by, thefollowing description.

In this respect, before explaining at least one embodiment of theinvention in detail, it is to be understood that the invention is notlimited in its application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the drawings. The invention is capable of otherembodiments and of being practiced and carried out in various ways whereparticular configurations, process steps, and materials disclosed hereinas such configurations, process steps, and materials may vary somewhat.In addition, it is to be understood that the phraseology and terminologyemployed herein are for the purpose of the description and should not beregarded as limiting. Furthermore, as will be apparent to those skilledin the art, the present invention may be embodied in other specificforms without departing from the essential characteristics thereof.

For purposes of the description of the drawings and the embodiments ofthe present invention, as mentioned for each drawing, each figure maynot drawn to scale. Some areas drawn may be bigger and/or simpler inorder to clearly portray the improvement to what has already beenestablished. It will nevertheless be understood that no limitation ofthe scope of the invention is thereby intended. Any alterations andfurther modifications of the inventive features illustrated herein, andany additional applications of the principles of the invention asillustrated herein, which would normally occur to one skilled in therelevant art and having possession of this disclosure, are to beconsidered within the scope of the invention claimed. It is also to beunderstood that the terminology employed herein is used for the purposeof describing particular embodiments only and is not intended to belimiting since the scope of the present invention will be limited onlyby the appended claims and equivalents thereof.

Various implementations of the subject matter described herein may berealized in digital electronic circuitry, integrated circuitry,specially designed ASICs (application specific integrated circuits),computer hardware, firmware, software, and/or combinations thereof.These various implementations may include implementation in one or morecomputer programs that are executable and/or interpretable on aprogrammable system including at least one programmable processor, whichmay be special or general purpose, coupled to receive data andinstructions from, and to transmit data and instructions to, a storagesystem, at least one input device, and at least one output device.

These computer programs (also known as programs, software, softwareapplications or code) include machine instructions for a programmableprocessor, and may be implemented in a high-level procedural and/orobject-oriented programming language, and/or in assembly/machinelanguage. As used herein, the term “machine-readable medium” refers toany computer program product, apparatus and/or device (e.g., magneticdiscs, optical disks, memory, Programmable Logic Devices (PLDs)) used toprovide machine instructions and/or data to a programmable processor,including a machine-readable medium that receives machine instructionsas a machine-readable signal. The term “machine-readable signal” refersto any signal used to provide machine instructions and/or data to aprogrammable processor.

To provide for interaction with a user, the subject matter describedherein may be implemented on a computer having a display device (e.g., aCRT (cathode ray tube) or LCD (liquid crystal display) monitor) fordisplaying information to the user and a keyboard and a pointing device(e.g., a mouse or a trackball) by which the user may provide input tothe computer. Other kinds of devices may be used to provide forinteraction with a user as well; for example, feedback provided to theuser may be any form of sensory feedback (e.g., visual feedback,auditory feedback, or tactile feedback); and input from the user may bereceived in any form, including acoustic, speech, or tactile input.

The subject matter described herein may be implemented in a computingsystem that includes a back-end component (e.g., as a data server), orthat includes a middleware component (e.g., an application server), orthat includes a front-end component (e.g., a client computer having agraphical user interface or a Web browser through which a user mayinteract with an implementation of the subject matter described herein),or any combination of such back-end, middleware, or front-endcomponents. The components of the system may be interconnected by anyform or medium of digital data communication (e.g., a communicationnetwork). Examples of communication networks include a local areanetwork (“LAN”), a wide area network (“WAN”), and the Internet.

The computing system may include clients and servers. A client andserver are generally remote from each other and typically interactthrough a communication network. The relationship of client and serverarises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other.

Although a few variations have been described in detail above, othermodifications are possible. For example, the logic flow depicted in theaccompanying figures and described herein does not require theparticular order shown, or sequential order, to achieve desirableresults. Other implementations may be within the scope of the followingclaims.

1. A method for determining an insulin dose to be administered by aninsulin delivery device based on a determined insulin sensitivity (IS),comprising: providing a subcutaneous glucose sensing apparatus, and theinsulin dispensing apparatus; and receiving a first parametercorresponding to a first insulin dose value administered by the insulindispensing apparatus in a subcutaneous tissue; applying a first kineticmodel to obtain a plasma insulin concentration based on the firstparameter; receiving a second parameter corresponding to a glucoseconcentration value from the glucose sensing apparatus; determining theinsulin sensitivity (IS) based on the plasma insulin concentration andthe second parameter; determining a second insulin dose value based onthe determined insulin sensitivity to be administered by the insulindispensing apparatus; and reevaluating the insulin sensitivity (IS)after a predetermined period of time since a last food bolus via aninsulin sensitivity assessment feature; and delivering an insulin bolusvia a cannula coupled to the insulin delivery apparatus.
 2. The methodof claim 1 wherein the first kinetic model comprises a one-compartmentkinetic model applied to obtain the plasma insulin concentration using acalculation including a first order absorption rate constant, a firstorder elimination rate constant, and a distribution volume.
 3. Themethod of claim 2 further comprising utilizing in the calculation a timecourse accounting for continuous subcutaneous insulin infusion at aconstant rate.
 4. The method of claim 1 further comprising adhering theinsulin delivery device directly to the skin of a patient.
 5. The methodof claim 1 further comprising sensing the glucose concentration value,via the glucose sensing apparatus, via the cannula that is penetratingand residing in a skin of a patient, residing in subcutaneous tissue. 6.The method of claim 1 further comprising sensing the glucoseconcentration value, via the glucose sensing apparatus, via a secondcannula penetrating and residing in a skin of a patient, residing insubcutaneous tissue.
 7. The method of claim 1 further comprisingcoupling the glucose sensing device directly to a top inner portion of ahousing of the insulin delivery device at a side farthest from a skinsurface, such that the glucose sensing device is coupled only to the topinner portion and not inner walls of the housing.
 8. The method of claim1 further comprising providing an opening in the glucose sensing devicefor receiving a test strip, the glucose sensing device coupled to ahousing of the insulin delivery device, the housing having an openingsuch that the test strip is placeable into the glucose sensing device.9. A method for determining an insulin dose to be administered by aninsulin delivery device based on a determined insulin sensitivity (IS),comprising: providing the insulin delivery device comprising a housingcontaining therein a glucose sensing device and an insulin dispensingapparatus, a cannula extending from the housing; receiving a firstparameter corresponding to a first insulin dose value administered bythe insulin dispensing apparatus in a subcutaneous tissue; applying afirst kinetic model to obtain a plasma insulin concentration based onthe first parameter; receiving a second parameter corresponding to aglucose concentration value from the glucose sensing apparatus;determining the insulin sensitivity (IS) based on the plasma insulinconcentration and the second parameter; and determining a second insulindose value based on the determined insulin sensitivity to beadministered by the insulin dispensing apparatus.
 10. The method ofclaim 8 further comprising reevaluating the insulin sensitivity (IS)after a predetermined period of time since a last food bolus via aninsulin sensitivity assessment feature.
 11. The method of claim 8further comprising delivering an insulin bolus via the cannula.
 12. Themethod of claim 8 further comprising coupling the glucose sensing devicedirectly to a top inner portion of the housing farthest from a skinsurface, such that it is coupled only to the top inner portion and notinner walls of the housing.
 13. The method of claim 8 further comprisingproviding an opening in the glucose sensing device for receiving a teststrip, the glucose sensing device coupled to the housing, the housinghaving an opening such that the test strip is placeable into the glucosesensing device.
 14. The method of claim 13 further comprising placingthe test strip into the opening of the glucose sensing device.
 15. Themethod of claim 7 further comprising extracting blood from a body,placing the blood on a test strip, and inserting the strip into anopening of the glucose sensing device.
 16. The method of claim 7 whereinthe first kinetic model comprises a one-compartment kinetic modelapplied to obtain the plasma insulin concentration using a calculationincluding a first order absorption rate constant, a first orderelimination rate constant, and a distribution volume.
 17. The method ofclaim 7 further comprising utilizing in the calculation a time courseaccounting for continuous subcutaneous insulin infusion at a constantrate.
 18. The method of claim 7 further comprising adhering the insulindelivery device directly to the skin of a patient.